The chemistry of pyridinethiols and related ligands .7. Preparation and spectroscopy of mixed-ligand copper(I) complexes: the crystal structure of first mixed-ligand dinuclear [iodo(pyridine-2-thione)(tri-p-tolylphosphine)copper(I)](2) complex

Direct reaction of copper(I) iodide with pyridine-2-thione (C5H5NS) and tri-p-tolyl phosphine (p-Tol(3)P) in 1:1:2 ratio in refluxing chloroform formed a product of stoichiometry, [Cul(C5H5NS)(p-Tol(3)P)](2) (5), whose X-ray crystal structure has been determined. It crystallises from a dichloromethane-ethanol mixture and exists as a centrosymmetric sulfur bridged dimer with distorted tetrahedral geometry-about each Cu atom; the other two positions of each Cu atom being occupied by a P atom from p-Tol(3)P and a iodine atom and the central core Cu2S2 of the dimer is planar. The interatomic important parameters are: Cu-P = 2.243(3), Cu-S, 2.393(4), 2.425(4), Cu-I, 2.603(2), C-S, 1.690(12) Angstrom, Cu-S-Cu, S-Cu-S, and Cu-S-C bond angles are 85.25(13), 94.75(13) and 107.0(4) respectively. The dimer structure is stabilised by strong intramolecular N-H ... I hydrogen bonds. The solution phase behaviour of 5 and other related mixed-ligand copper(I) complexes, [CuX(C5H5NS)L](2) [X = Cl, L = p-ToI(3)P (1), X = Br, L = m-Tol(3)P (2), p-Tol(3)P (3), X = I, L = m-Tol(3)P (4) is also studied using electronic absorption and multinuclear (H-1, C-13 and P-31) NMR spectroscopy. (C) 1997 Elsevier Science Ltd.